Write Notes on Electrospray Ionization.

Electrospray Ionization:

Electrospray Ionization (ESI) uses electrical energy to assist the transfer of ions from solution into gaseous phase before they are subjected to mass spectrometric analysis.

During standard ESI, the sample is dissolved in a polar, volatile solvent which is prepared by mixing water with volatile organic compounds like methanol.

ESI involves three steps.

1) Dispersal of a fine spray of charged droplets.

2) Followed by solvent evaporation , and

3) Ion ejection from the highly charged droplets.

Question: Discuss the application of DNA fingerprinting in medicine and evolutionary studies.

DNA profiling has wide range of applications.

Application in medicine: 

i) Genetic disease diagnosis: Many disorders like Huntington's disease, Haemophilia, cystic fibrosis, Alzheimer's disease can be diagnosed by using DNA fingerprinting. With this technique genetic tests for genetic disorders have become quick and more effective.
 By employing DNA fingerprinting, with a single drop of mother's blood, doctors can find out if the fetus has any genetic abnormality or not. This technique is much safer and sophisticated for this kind of diagnosis.

VNTRs and Their Classification

• VNTR: 

• Repetitive DNA composed of copies of a short sequence ( DNA motif) is called as VNTR or Variable Number of Tandem Repeats.
      Its a location in a genome where a short nucleotide sequence is organised in a tandem repeat.

• Classification of VNTRs:
• VNTRs can be classified into two types, microsatellite and minisatellite. 

Significance of TCA cycle

TCA cycle is not only a pathway for oxidation of two carbon units, but is also a major pathway for interconversion of metabolites arising from transamination and deamination of amino acids, and providing the substrates

TCA Cycle- Regarded as amphibolic

• TCA cycle provide many intermediates for the synthesis of many compounds needed by the body. It is actively involved in gluconeogenesis, transamination & deamination. 

Porphyrias

Definition: 

Porhyrias are metabolic disorders of heme synthesis, categorised by increased excretion of porphyrins or porphyrin precursors.

Porphyrias are either inherited or acquired. They are broadly classified into two major groups.

Preservation Techniques for Industrially Important Microorganisms

Question: What are the preservation techniques for maintenance of the industrially important microorganisms ?

Answer:

For industrially important microorganisms, maintenance of the desirable strains is very much important. Preservation of these strains ensure optimal long time viability, genetic stability and purity of the microorganism. Several  preservation methods have been developed and they are as follows,

1. Periodic Transfer to Fresh Media: Strains can be maintained by periodically preparing a fresh subculture from previous stock culture. The culture medium, the storage temperature and the time interval at which the transfer undergoes , varies depending upon the species. The temperature and the growth medium should  support a slow growth rather than a rapid one in order to make the time interval between transfers as long as possible.

Artificial Transformation and the role of calcium chloride-heat shock treatment

Question: What are the roles of CaCl2  and heat shock in artificial transformation ? 

Answer: 

Artificial transformation is accomplished by inducing competence in cells by using chemicals or electroporation. The most common method of making competent cells is CalCl2 and heat shock treatment. In this technique an early log phase culture is centrifuges and re-suspended in a cold, hypo-tonic CalCl2 solution, and after that DNA is added to these cells, followed by a brief heat shock, which allows transportation of the DNA into the cell. The roles that CalCl2 and heat shock play in accomplishing this, are as follows-